Inserted tooth saw



NOV- 21, Q ORR INSERTED TOOTH SAW Original Filed Feb. 25, 1950 Elijah [lljni 7 7 altozweq Patented Nov. 21, 1933 I 1,936,242 INSERTEDTOOITH'SAWV Elijah o. Orr, satfle, Wash'." I lRefiled for abandoned application Serial. No. I

. -43 1,109, February-25, 1930.

This application Mal-ch 8, 1932. Serial No.;597,603

screa (c lia-151) My invention relates to inserted tooth saws and consists of an improved constructionof tooth and holderand to the combination of such tooth and holder with the saw body and with the peculiar 5' type of tooth and holder-receiving'recess in the saw body. a I 7 One object of my-invention is to'provide a construction for theseparts such that the teeth are better held in place without excessive. strain upon any'part: also,- a construction in which the parts are stronger and lesslikely to break in useand one which will better care for and accommodate the saw dust and prevent its working'rearw'ardly past the teeth, thereby preventing a considerable source of friction; thereby reducing the power required to turn the saw.

Another'object is to provide for the insertion of a greater number of teeth than may be employed in saws of the same. size and employing other constructions, without thereby weakening the saw body or the tooth parts.

-My present invention consists in part of a tooth and a holder therefor, both constructed to give better strength and to cooperate to give superior operating results. This is in part secured by a design'ofthe parts which will securely hold the teeth and at the same. time avoiding unnecessary strain of the parts-due merely to the act of insertion and-entirely apart from strains caused by the work of cutting. Such strains, arising from conditionscausedby the insertion of teeth and operative while the. saw is at rest, often leave such asmallr'nargin of strength with which to'resist the added strains of cutting, that many teeth are broken- My invention alsoconsists in part, of a design of holder which'may be used to secure several different designs of teeth in the same saw, it being necessary only to modify-theholder in that part which engages the teeth, toconform to difierences in teeth, ifthere' be such in the part which engages the holder. The'accompanying ferred embodiments of my invention. In these the same reference character indicates the same partinallfigures.

Figure l shows a small section of the peripheral part of a'saw'body and two-teeth inserted therein. 3 1 H Q Figure'Z shows similar parts which differ slightly in construction. 7

Figure 3 shows a single tooth assembly of another construction.

Figure 4 is a front face or edge' view'jof atooth' such as is shown in Figure 1.

drawing illustrates pre- Figure 5 is a transverse section of a tooth on V a line corresponding with the line 5-5 of Figure 4;

: Figure 6 is a tooth section on line 6-6 of Figure 1. r

In the drawing 1 represents the saw body. This is provided with peripheralrecesses shaped t o-receive and hold tooth assemblies; each consisting of'a tooth and a holder. The tooth 3 comprises ashank 30, a-holding teat or'projection 31 and a head 32 which terminates in the. cutting tip The holder 2 has a pivot head 20, a central thrust bar, body or shank 21 and a head 22 having an arcuate outer edge 28, having its center 00- 7o incident with or adjacent to the center of the are 13 of the pivot head; The saw body is out out to receive and securelygrip and hold the tooth holder when in place. The arcwhichengage's the periphery of the pivot head of-the tooth holder, preferably exactly conforms to the complemental are of the-pivot head, while the arc l0, of the saw body does'not exactly conform in curvature with'that of the engaging are 28 of the tooth holder, as will later be explained. I f The tooth3'hasa shank 30, a thickenedhead -32'and' a holding ori'locking teat or finger 31,

the latter entering'a'complemental recess in the arcuateedgeofthe holder. 7 The above features in their bread aspects are similar to previously used and standard constructions, but difier in details which arefbelieved to contribute materially towards improved re' 'sults.

p The arcuate edgeslil and 13 of the saw are concentric with the'saine center, the'position of this beingindicated in l igur l at A, while the arcuate edge 23 of the hoider'which, engagesthe edge 10, is concentric with a point farther removed, or indicated at B. The radius of thearc 28 of the holder being greater thanthat of 1 the are 19 and the two arcs being tangent' at a pointfas 5, the are 28 ofthe holder would,

towards its ends, pass slightly without the are 10. Thishas been indicated on the drawingby the broken line 10 in Fig.1. The differenceof radii would be determined by experience and consideration of thecharacter'of material used. The heel section of the holder has a slot 4 forming a finger-40 whichhas su fiicient resiliency to yield inwardly when inserted, as is indicated in Figures 1, 2 and 3 by'the convergence of the side walls of'thefslot; This yielding has possibly been exaggeratedto better illustrate the fact. Bythis' expedient a secure but yielding grip is secured between the holder and the edge of the receiving recess, which prevents outward movement of the holder under centrifugal force generated in running and yet permits removal when desired.

The upper or outer arm 24 of the tooth holder is not slotted to provide resiliency for the reason that it engages the edge 10 of the saw body for only a short distance from the point 5 and also because its dimensions are such that it will have a measure of resiliency sufficient for the purpose without slotting.

The pivot end of the holder is provided with a hole 26 which is located without consideration of agreement with either of the centers used in striking the arcs referred to. The chief purpose of this hole is to receive one pin of a spanner or wrench used for inserting and removing the tooth holder and tooth. The heel portion of the holder is provided with a hole 41 having a like purpose. In some, and possibly in most cases, the hole 26 is connected with the throat edge of the holder by a slot 27 which permits yielding of the arm thus formed. Because of this the radius of the holder head may be made slightly larger than that of the receiving recess in the saw, the pivot head yielding when inserted.

The contacting edges of tooth, holder and saw body, are preferably of the standard rib and groove construction which prevents relative side movement, with the exception of the straight edge 29, where such construction is hardly needed. The upper arm or tip 24 of the holder head engages the inner edge of the tooth shank 30. This arcuate edge of the holder is designed to be slightly larger than the inner edge of the tooth, which latter is, in Figures 1 and 2, a continuation of the are 1 0 of the saw body. The finger 24 must, therefore, yield slightly when the tooth is inserted. The finger 24 is of a proportion and dimension which permits yielding. The saw tooth shank is thus firmly gripped and by reason of the rib and groove construction of the engaging edges, and by further reason of the fact that the holder head is itself firmly held against side movement by reason of like construction of the engaging arcs 10 and 28, the tooth is firmly held against side movement. The firmness of this grip and holding effect isheightened by the fact that the arcs 10 and 28 are of relatively much larger radius than analogous portions of previous constructions.

The tip of arm 24 is preferably rounded over to provide a measure of thrust support for the tooth and also to increase the cross section of the tooth at this point and its strength at the point of maximum breaking effort. This is more pro- 'IIOlHlCBdIY indicated in Figure 3.

The tooth head 32 is thickened, as is custernary, and this is preferably carried far enough back to overlap the arm 24 of the'holder, while the forward or throat edge of the holder is also preferably thickened, making a slight rib 25 at each side.- This thickening extends well down towards the bottom of the throat. The thickness of the front edge of the holder is kept somewhat less thanthe width of the kerf made by the saw. V

The straight front or grinding face of the tooth, together with the succeeding curved face 34, as well as the front edge of the arm 24 of the holder, are hollow ground, that is, this edgeis concavely curved in cross section. This provides a curved cutting edge at the cutting tip 33 which produces smoother cutting and also provides edges throughe out the hollow ground portions which will function as cutting edges to act upon any sawdust or slivers which may occupy the throat.

There is always a tendency for the sawdust to crowd past the teeth and to the rear. This wedges the sawdust between the side surfaces of the saw and kerf, often producing considerable friction and consuming power. With proper hollow ground faces at the rear side of the throat, such sawdust will be either forced toward the center line of the'kerf or be cut, thereby reducing the amount which can crowd past the teeth and reducing its size, both effects which reduce the friction and the power consumption. The hollow ground feature of the back edge of the throat is very effective in crowding the sawdust to the center plane of the kerf and preventing its crowding past the teeth.

The length of the arcuate section 10 of the saw body is a little more than the arc of movement required to insert and remove the tooth, so that with the tooth entirely cleared, as is shown by the tooth at the left in Figure l, the holder is stillsecurely held in place. In the construction shown in Figure l, the thrust bearing or support for the tooth is at its lower end. The arcuate edge ll of the saw body which engages the outer edge of the tooth has a center common with the are 10, that is, at A.

The construction shown in Figure 2 differs from that of Figure l in having .the thrust abutment for the tooth at the rear of its head, or at 15, instead of at the inner end of the shank.

In Figure 3 the outer face of the outer section 50 of the tooth holder is modified by being made an arc of a circle of shorterradius,the center being at D. This modifies the shape of thetooth shank in two ways. The WidthOf the tooth at about the rear of its head, that is at orinwardly of the outer tip of the prong 16 of the saw body, is greater than in the otherfigures, thus strengthening the tooth where it ismost likely to break.

Also, the narrowest part-of the shank is somewhat outwardly of its inner end and the enlarged inner end of the shank provides an-efiicient holding element for the tooth. The small holding teat is therefore not the only holding means, and may in fact, be dispensed with.

In the construction of Figure 3 the forward face of the tooth is. supposed to be concavely rounded or hollow ground, as is alsothe front edge face of the holding arm of the tooth holder. This hollow grinding runs to the inner end of; the tooth shank that is, to the teat-3 1 Q' In a tooth holder of the type illustrated-the edge which grips the sawbody, that-is, the edge 28, is an arc of comparatively large radius and approaches, throughout the greater part of its length, the direction of -a radius of the saw. At

the same time the innermost edge ofv the holder is straight and lies but little inwardly of the pivot point of the holder. In consequence, the recess in the saw is not relatively a deep one. The various parts reinforce each other to thoroughly support the teeth and to grip them securely.

In removing a tooth it is not necessary to remove the holder. It need be turned only as-far as is indicated for the left-hand tooth in Figure 1. There is thus only one member loosened or removed in replacing a tooth. This-obviates the frequent misplacement or loss of holders-when re placing teeth. r V v The shape and design of both tooth-and holder makes it possible to easilymill all edges which e u e m ll g- What i claim as my invention is:

taining tooth receiving recesses having at one end a pivot bearing for a tooth holder and at the other end a ci'rcular-arcuat'e edge havingits centersubstantially coincident with that of the pivot head, and a holder having at one end a pivot bearing complemental to. and engaging the pivot bearing of the saw body and at its other end an arcuate edge of slightlydifierent radius from that of the; complemental arc of the saw body, said arcs ofholder and saw body being tangent at a point outwardly of their inner ends, the holder having a slot located inwardly of one end of said arcuate edge to provide a yielding finger which permits that section of said are conforming in curvature with that of the saw recess when the holder is turned to its final position.

2. In an inserted tooth saw, a saw body having recesses for the teeth and their holders, said recesses having at one end a circular arcuate section forming a pivot bearing for a tooth holder and at its opposite end having an inner arouate segment also-concentric with the pivot bearing but of a larger, radius and an outer segment concentric with the pivot bearing but of sufficiently larger radius to provide a tooth receiv-' ing recess, atooth havingthe outer edge of its shank engaging said outer arcuate segment of the saw body and its inner edge forming an outward extension of the inner arcuate segment of the saw body,. a tooth holder having a pivot head fitting and turnable in the pivot bearing and a head provided with an arcuate edge concentric with a point adjacent to and beyond the pivot center and tangent with the arcuate segment of the saw body at a point outward of its inner end, said arcuate edge of the holder engaging the complemental arcuate edges of the saw body and tooth shank, the holder having.

a slot extending from its inner edge back of its said arcuate edge to thereby provide a yielding finger at the inner end oi said arcuate edge.

3. A tooth holder for inserted tooth saws having a pivot head, an arm radially disposed rel- .ative to said pivot'head, and a holding arm extending outwardly from the swinging end of the radial arm, the outer edge'of said holding radial arm and having an outer arcuate edge concentric with a point positioned slightly beyond the pivot axis, the holder having a slot extending from the inner edge of the radial arm inwardly of said .arcuate edge to thereby provide a short yielding finger at the inner part of said ,arcuate edge. v

.5. A tooth holder for inserted tooth saws having an arcuate pivot head adapted to fit and turn in a complemental recess in the saw body, said holder having an arm extending radially from the pivot head and'a holding arm extending outwardly of the saw from its swinging end, the outer edge of said holding arm being of circular-arcuate outline with its center positioned slightly beyond the. pivot center, the out- Wardly facing edge of said holder being curved on the holder, said holder being provided with means which permit a slight inward yielding towards the ends of its said arc.

'7. A tooth andholder for inserted tooth saws having the forwardly facing edges of both transversely hollow'ground.

8. A tooth holder for an inserted toothsaw having an edge thereof forming the rear wall of the throat and thickened to a little less than.

the thickness-of the kerf out and transversely hollow ground. ELIJAI-I C. ORR. 

